HOW TO TEACH RELATIVITY TO YOUR DOG

Another quirky science primer from the author of How to Teach Physics to Your Dog (2009).

Traditional popular-science books often feature a teacher answering a child’s naïve but astute questions. Orzel’s (Physics/Union Coll.) talking dog is original without being an improvement. Unlike quantum physics, which remains bizarre even to experts, much of relativity makes sense. Thus, Einstein’s special relativity merely states that the laws of physics and the speed of light are identical for all observers in smooth motion. This sounds trivial but leads to weird if delightfully comprehensible phenomena, provided someone like Orzel delivers a clear explanation of why, for example, a stationary observer sees clocks running slower (and so time passing slower) on a moving body. The faster it moves, the slower the clock. Clock and time stop cold at the speed of light, but only the outside observer sees this. Anyone on the moving object sees time passing normally. Having covered other experimentally proven space-time oddities (moving bodies also shrink), Orzel moves on to gravity, the province of general relativity—no less strange but understandable in his expert hands. Under Newton’s gravity, objects attracted each other magically across empty space. Einstein provided an explanation; massive bodies warp nearby space, so moving bodies follow the shortest path. Relativity is comprehensible but not simple; comic books have claimed to teach it, but readers discover that cheerful cartoons or animal humor don’t eliminate the requirement of reading, perhaps rereading, and reflecting.

Those willing to skim the cute teacher-dog exchanges will find themselves in the hands of a skilled educator.